This invention relates to oxidation colorants containing special indoline derivatives in combination with secondary intermediates for coloring keratin fibers.
By virtue of their intensive colors and good fastness properties, so-called oxidation colorants play a prominent role in the coloring of keratin fibers, particularly human hair. Oxidation colorants normally contain oxidation dye precursors, so-called primary intermediates and secondary intermediates. The primary intermediates form the actual dyes with one another or by coupling with one or more secondary intermediates in the presence of oxidizing agents or atmospheric oxygen.
Good oxidation dye precursors are expected to satisfy above all the following requirements: they must form the required color tones with sufficient intensity and fastness during the oxidative coupling reaction. In addition, they must be readily absorbed onto the fibers with no significant differences--particularly in the case of human hair--between damaged and freshly regrown hair (leveling behavior). They must be resistant to light, heat and the effect of chemical reducing agents, for example permanent wave lotions. Finally, if they are used to color hair, they should not overly stain the scalp and, above all, should be toxicologically and dermatologically safe.
The primary intermediates used are, for example, primary aromatic amines containing another free or substituted hydroxy or amino group in the para position or the ortho position, diaminopyridine derivatives, heterocyclic hydrazones, 4-aminopyrazolone derivatives and 2,4,5,6-tetraaminopyrimidine and derivatives thereof.
Special representatives are inter alia p-toluylenediamine, p-aminophenol, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, 2-(2,5-diaminophenoxy)-ethanol, 1-phenyl-3-carboxyamido4-amino-5-pyrazolone and 4-amino-3-methylphenol and 2,4,5,6-tetraaminopyrimidine.
The secondary intermediates are generally m-phenylenediamine derivatives, naphthols, resorcinol and resorcinol derivatives, pyrazolones, m-aminophenols and pyridine derivatives. Particularly suitable secondary intermediates are 1-naphthol, pyrogallol, 1,5-, 2,7- and 1,7-dihydroxynaphthalene, 5-amino-2-methylphenol, m-aminophenol, resorcinol, resorcinol monomethyl ether, m-phenylenediamine, 1-phenyl-3-methyl-5-pyrazolone, 2,4-dichloro-3-aminophenol, 2,4-diaminophenoxyethanol, 1,3-bis-(2,4-diaminophenoxy)-propane, 2-chlororesorcinol, 2-chloro-6-methyl-3-aminophenol, 2-methyl resorcinol, 2,6-dihydroxypyridine, 2-aminomethyl-3-amino-6-methoxypyridine and 2,6-diaminopyridine.
With regard to the dyes suitable for use in the hair coloring and tinting formulations according to the invention, reference is also specifically made to Ch. Zviak's work The Science of Hair Care, Chapter 7 (pages 248-250; Substantive Dyes) and Chapter 8, pages 264-267; Oxidation Dye Precursors), published as Vol. 7 of the Series "Dermatology" (Editors: Ch. Culnan and H. Maibach), Marcel Dekker Inc., New York/Basel, 1986 and to the "Europaische Inventar der Kosmetik-Rohstoffe" published by the Europaische Gemeinschaft and available in diskette form from the Bundesverband Deutscher Industrie- und Handelsuntemehmen fur Arzneimittel, Reformwaren und Korperpflegemittel e. V., Mannheim, Germany.
In general, natural color tones cannot be obtained with a single secondary intermediate/primary intermediate combination. In practice, therefore, a combination of various primary intermediates and secondary intermediates has to be used to obtain a natural-looking color. So-called substantive dyes may also be required to adjust the particular color tone required.
Accordingly, there is a constant need for new improved colorants.
In recent years, corresponding investigations have shown indoline derivatives to be suitable, particularly for hair colorants. Thus, EP-B1-0 530 229 describes the use of 5,6-dihydroxyindoline derivatives as secondary intermediates in oxidation colorants. This document discloses colorants which, besides the indolines, contain typical primary intermediates and/or substantive dyes. Colorants additionally containing typical secondary intermediates are not mentioned in this document. EP-B1-0 613 366 relates to the use of the same 5,6-dihydroxyindoline derivatives for improving the coloring properties of formulations based on substantive dyes or on oxidation dye precursors of the secondary intermediate and primary intermediate type. The combination of these 5,6-dihydroxyindolines with oxidation dye precursors of the secondary intermediate type alone is not mentioned in this document.